1. COMPUTERS

2. What is a computer?
 It is a set of electronic devices that can systematically and
sequentially follow a set of instructions called a program to
perform high-speed arithmetic and logical operations on data.
A computer basically processes data to give information.
 The areas of application of computers span almost every field
of endeavour namely
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manufacturing, commerce, business, librarianship,
engineering, archives administration,
records management, medicine, entertainment,
military manoeuvring, finance,
law and crime, banking

3. Advantages of Computers
– Accuracy
– Speed (faster)
– Undertake complex processing
– Stores large volume of data/information
– Cheaper in terms of processing data compared with
manual processing

4. Disadvantages of Computers
 Expensive (Cost of buying and maintenance)
 It creates unemployment
 It is human dependent
 It is also highly dependent on external power
 Associated with harmful effects e.g. radiation,
stress, bad posture, isolation, etc

5. Functional Structure of Data Processing
System (Computer)
Data:
 is raw or unrelated facts or
figures without meaning or raw
facts about an event or activity
or entities.
Information:
 is processed data with meaning.
Program:
 a set of instruction that the
computer follows in order to
perform its functions or
operations.
Input
(Data)
Processing
(Program)
Output
(Information)

6. Six Basic Functions of a Computer
1.Input
The process of sending data into the computer using input devices like
mouse, keyboard, joystick, bar code reader, monitor, etc.
2. Processing
The changes or manipulation that data undergoes to become information.
It simply the conversion of raw input into a form that is more meaningful to
humans. This is achieved by using a computer program; and it is done in
the systems unit (processor, memory, storage devices, ALU).
3. Output
Is the result that comes out after processing of data- information; using
devices like printer, speaker, plotters, monitor, etc. An output could be in
two forms: softcopy output (onscreen output) or hardcopy output (printed
output).

7. Six Basic Functions of a Computer
4. Filing
Computers store data or information using filenames and extension
names. E.g. micky.doc, micky.xls, micky.html, etc
5. Sorting
Computers are capable of arranging files, data, and records in a predefined
order. Computers sorts data/information during storage either by name,
date, size, etc
6. Control
Putting checks on processes to meet the criteria for evaluating operations.

8. TYPES OF COMPUTERS
Super computers
The largest, most powerful and most expensive
computers in the world, with high processing and
storage capacity.
They are used by large organizations normally
government sponsored organizations, for highly complex
activities such weather forecasting, space exploration,
etc.
The IBM's Sequoia and Bitcoin Network are amount the
fastest in the world

9. TYPES OF COMPUTERS
Super computers
The largest, most powerful and most expensive
computers in the world, with high processing and
storage capacity.
They are used by large organizations normally
government sponsored organizations, for highly complex
activities such weather forecasting, space exploration,
etc.
The IBM's Sequoia and Bitcoin Network are amount the
fastest in the world

10. TYPES OF COMPUTERS
Mainframe computers
Large computers, capable of great
processing speeds and data storage.
Use by large organizations who handle
large volumes of data – banks,
– universities,
– Insurance companies etc.
It normally supports database
accessibility by mini/micro computers.

11. TYPES OF COMPUTERS
Mini or Midrange computers
A midrange computer is a
medium-sized computer
system or server that covers
a very broad array and
resides in capability between
high-end PC servers and
mainframes.
They usually fall in between
mainframe computers and
microcomputers.

12. TYPES OF COMPUTERS
Micro-computers
The smallest of the types of computers. Consist of microprocessor chip. There are two types,
portable microcomputers (e.g. laptops, notebooks, palmtops, tablets, smart phones, etc.),
and Desktop small enough to fit unto a desk but large enough to be carried about (e.g. PC).
Suited for offices and homes. Comes with interfaces that permit the use of peripheralsscanner, printer, speakers etc. or sharing of these facilities